A preliminary study on the effects of jejunocaecostomy in horses

Summary Ileal bypass by re-section and jejunocaecostomy is a commonly performed surgery in horses, but has a reportedly lower success rate than other small intestinal surgeries. Lower success rates and chronic problems with diarrhoea, weight loss, protein, sugar and fat malabsorption, and Ca/P imbalance occur in man. The purpose of this study was to investigate changes in bodyweight, nutrient digestion and absorption, and serum and urine composition in horses before and 3, 12 and 27 weeks after ileal resection and side-to-side jejunocaecostomy. Four adult, healthy horses had a baseline CBC; serum creatinine, cholesterol, Na, K, Cl, Mg, Ca, P; digestion trial; xylose and fat absorption test; and serum total bile acid test. Digestion of dry matter, crude protein, total plant cell wall, cellulose, hemicellulose, and lignin; and urinary fractional excretions of Na, K, Cl, P and Ca were calculated. A one-way analysis of variance compared baseline values to those obtained after caeliotomy and jejunocaecostomy (P<0.05). Results include a significant decrease in serum calcium and total protein 27 weeks after surgery and a significant increase in FENa, FECa, and faecal metabolic organic matter 27 weeks after surgery. Bodyweight decreased significantly 3 weeks after surgery, but increased to greater than baseline values at 12 and 27 weeks after surgery. Vitamin A absorption curves were normal (sigmoid) before surgery and linear at all times after surgery. Serum cholesterol was significantly lower 27 weeks after surgery and a trend (P<0.1) for a lower serum cholesterol was observed 3 weeks after surgery. No significant differences were apparent in serum electrolytes, faecal water, protein or fibre digestibility, xylose absorption or serum bile acid measurements. In summary, ileal bypass affected the horses minimally, but derangements of Ca metabolism, fat (fat soluble vitamin) absorption and microbial flora need further study.